System and method for cellular network identification

Abstract

A method for identifying cellular networks using a computer processor and a signal receiver including determining whether a cellular network being used is either an LTE-DL, LTE-UL, GSM, CDMA2000 or UMTS network. The determination is made on the basis of individual tests eliminating one network at a time based on unique characteristics of each particular network.

The invention claimed is: 
     
       1. A method for identifying cellular networks using a computer processor and a signal receiver comprising:
 (i) applying a signal magnitude test to determine whether magnitude of observed cellular signal samples follows a predetermined distribution representative of LTE-DL (long term evolution downlink) signals; 
 upon a condition in which said observed samples follows said predetermined distribution, outputting an indication that a signal is from an LTE-DL network and terminating the method; 
 (ii) applying a test to determine the presence of a cyclic prefix; 
 upon a condition in which the presence of the cyclic prefix is detected, outputting an indication that said signal is from an LTE-UL (long term evolution uplink) network, and terminating the method; 
 (iii) applying a test to determine whether the signal samples have a constant envelope; 
 upon a condition in which said signal samples have a constant envelope, outputting an indication that said signal is from a GSM network, and terminating the method; 
 (iv) applying a test to determine a signal bandwidth estimate to determine whether said signal samples are from CDMA2000 (code-division multiple access) or UMTS (universal mobile telecommunications system) networks; and outputting an indication of either the CDMA2000 or UMTS networks 
 wherein the observed cellular signal samples are received by a single receive antenna and are of the form y n =x n +w n , n=0, 1, . . . , N−1, where x n  represents the transmitted signal which belongs to either LTE-DL, GSM, LTE-UL, UMTS, or CDMA2000 networks, N is the number of observed samples, and w n  is the complex additive white Gaussian noise (AWGN) with zero-mean and variance σ w   2 . 
 
     
     
       2. The method of  claim 1 , wherein the magnitude test is a Kolmogorov-Smirnov test, and wherein the predetermined distribution is a Rayleigh distribution. 
     
     
       3. The method of  claim 1 , wherein said test to determine the presence of a cyclic prefix is a second-order one-conjugate correlation test. 
     
     
       4. The method of  claim 1 , wherein said test to determine whether the signal samples have a constant envelope is a one-sample Kolmogorov-Smirnov test. 
     
     
       5. The method of  claim 1 , wherein a bandwidth of 1.25 MHz is used to indicate the CDMA2000 network and a bandwidth of 5 MHz is used to indicate the UMTS network. 
     
     
       6. A method for identifying cellular networks using a computer processor and a signal receiver comprising:
 (i) applying a test to determine whether observed cellular signal samples have a constant amplitude; 
 upon a condition in which said observed samples have a constant amplitude, outputting an indication that a signal is from a GSM network; 
 (ii) applying a test to determine the presence of a cyclic prefix; 
 upon a condition in which the presence of the cyclic prefix is detected, determining a peak to average power ratio of the signal; wherein a high peak to average power ratio is indicative of an LTE-DL signal and a low peak to average power ratio is indicative of an LTE-UL signal; and outputting a corresponding indication of either the signal is from either an LTE-DL or LTE-UL network; 
 (iii) applying a test to determine a signal bandwidth estimate to determine whether said signal samples are from CDMA2000 (code-division multiple access) or W-CDMA networks; and outputting an indication of either the CDMA2000 or W-CDMA networks 
 wherein the observed cellular signal samples are received by a single receive antenna and are of the form y n =x n +w n , n=0, 1, . . . , N−1, where x n  represents the transmitted signal which belongs to either LTE-DL, GSM, LTE-UL, UMTS, or CDMA2000 networks, N is the number of observed samples, and w n  is the complex additive white Gaussian noise (AWGN) with zero-mean and variance σ w   2 .